Fluorinated beta-diketones

ABSTRACT

WHEREIN Ar is a perfluoro aromatic radical and N HAS A VALUE OF 0 TO 15. The compounds are produced via the Claisen condensation of an acetylaromatic compound and the lower alkyl ester of a perfluoroacid.   A new class of compounds useful, for example, as metal extractants is provided. The compounds are Beta -diketones of the formula

United StatesPatent [191 Chappelow, Jr. et a].

[ June 26, 1973 FLUORINATED BETA-DIKETONES [7S Inventors: Cecil C.Chappelow, Jr.; James F.

Engel, both of Kansas City, Mo.

[73] Assignee: Kerr-McGee Corporation,

Oklahoma City, Okla.

[22] Filed: Sept. 4, 1970 [21] Appl. No.: 69,939

OTHER PUBLICATIONS Reid et al., J. Am. Chem. Soc. 72, 2948-2952 1950Primary Examiner-Daniel D. l-lorwitz Attorney-William G. Addison [57]ABSTRACT A new class of compounds useful, for example, as metalextractants is provided. The compounds are B-diketones of the formulawherein Ar is a perfluoro aromatic radical and n has a value of 0 to 15.The compounds are produced via the Claisen condensation of anacetylaromatic compound and the lower alkyl ester of a perfluoroacid.

6 Claims, No Drawings FLUORINATED BETA-DIKETONES BACKGROUND OF THEINVENTION Certain organic compounds are known to have the ability tochelate metal ions. Thus, it is known that the compoundZ-thenoyltrifluoroacetone has extractive capability in metallurgicaloperations. However, there is a need for additional compounds having thecapability of functioning as selective extractants for various metalions.

SUMMARY OF THE INVENTION In accordance with this invention, certainnovel perfluorinated aromatic B-diketones have been discovered. Thesecompounds are capable of chelating metal ions.

The novel compounds of the present invention are represented by theformula wherein Ar is a perfluoro aromatic radical having from six to 14ring carbon atoms and n has a value of0 to 15.

By the term perfluoro is contemplated hydrocarbon moieties inwhich allfree hydrogen atoms have been replaced by fluorine. Thus, the radical Armay be pentafluorophenyl, heptafluorotolyl, heptafluoronapu by], andnonafluorobiphenyl and where -(CF ),,CF may be any of a variety ofperfluoroaliphatic radicals, such as trifluoromethyl, pentafluoroethyl,heptafluoropropyl and pentadecafluoroheptyl radicals.

The aromatic radical may be substituted by perfluorinated lower alkylgroups. Examples of suitable lower alkyl groups include methyl, ethyl,n-propyl, iso-propyl, n-butyl, sec-butyl and tert-butyl.

Examples of the group Ar include the perfluoro derivatives of phenyl,tolyl, xylyl, n-propylphenyl, secbutylphenyl, naphthyl, biphenyl andanthracyl radicals.

Examples of the radical -(CF,),,CF include fluoro substituted straightand branched chain alkyl groups where n is 0 to 15. Examples of suchgroups include perfluoro derivatives of methyl, ethyl, n-propyl,isopropyl, n-butyl, iso-butyl, tert-butyl, n-hexyl, n-octyl, iso-octyl,n-decyl and n-dodecyl radicals.

Representative compounds are 4,4,4-trifluoro-l- (pheptafluorotolyl)-l,3-butanedione, 4,4,5,5,5-pentafluoro- 1(2-heptafluoronaphthyl)-1,3-pentanedione and 4 ,4 ,4-trifluoro-l-pentafluorophenyl- 1 ,3 butanedione.

The compounds of this invention may be prepared by reacting an acetylsubstituted perfluoroaromatic compound of the formula with an ester ofthe formula wherein Ar and n have the values as defined hereinbefore andR is a lower alkyl, preferably ethyl.

The reaction is via Claisen condensation of the above compoundsconducted in the presence of a sodium alkoxide as the catalyst and anether solvent.

Preferred catalysts are sodium methoxide and sodium ethoxide. Exemplaryether solvents are diethyl ether and tetrahydrofuran. The reaction takesplace in accordance with the following:

The foregoing description and the following specific examples are forpurposes of illustration, and are not to be considered as limiting thescope of the invention, reference being had to the appended claims forthis purpose.

EXAMPLE I 4,4 ,4-Trifluorol -pentafluorophenyl-1 ,B-butanedione Driedsodium methoxide (0.1 mole) was suspended in anhydrous ether ml.). Ethyltn'fluoroacetate (14.2 g., 0.1 mole) in anhydrous ether (15 ml.) wasadded dropwise to the stirred suspension. During the exothermicreaction, nearly all of the sodium methosice reacted.Acetylpentafluorobenzene (21.0 g., 0.1 mole) in anhydrous ether (15 ml.)was added dropwise. This reaction was exothermic and the remainder ofthe sodium methoxide reacted. The resultant 'yellow, homogeneousreaction mixture was allowed to stand at room temperature overnightunder a nitrogen blanket. Work-up was effected by addition ofconcentrated sulfuric acid (3 ml.) in water (30 ml.) followed byextraction with ether and washing with water. The ethereal extract wasdried over anhydrous sodium sulfate and evaporated in vacuo. The crudeproduct was disti lled through a column packed with glass helices, 14.8g., b.p. 7779 l4.7 toi'r (48.4 percent yield). A gas chromatogram 2meter 20 percent SF-96 on Chromosorb P) of the pure liquid showedretention time of 5.6 min. An infrared spectrum (oil smear) of thecompound showed strong absorption centered at 1620 din- (C=O) and abroad region centered at 1180 cm- (C -F). The UV spectrum indicated Amaximum n hexane 289 mu E 10,820) The NMR spectrum (ref. "S'iZC'HDLJpossessed a broad peak of chemical shift 13.7 ppm for the enolichydrogen and a sharp singlet at 6.2 ppm for the olefinic hydrogen. A FNMR spectrum (ref, Freon 11) displayed a peak of chemical shift 76.8 ppmfor the methyl fluorines and peaks at 137.6 ppm, 146.7 ppm, and 159.3ppm for the ortho, para, and meta aromatic fluorines, respectively.

AricllfCalcd. for C H FiOz: C, 39.23; H, 0.66; F, 49.65. Found: C,39.31; H,0.69; F, 49.60.

' EXAMPLE n 3 mixture to stand at room temperature overnight under anitrogen blanket, 3 ml. of concentrated sulfuric acid and 30 ml. ofwater was added. The mixture was extracted with ether and the extractswashed with water. The ether solution was dried over anhydrous sodiumsulfate and evaporated in vacuo. The crude product was distilled througha Vigreaux column to give 12.4 g., b.p. 8398/2-.9 torr, which containedsome higher boiling impurities, as shown by gas chromatography (150C, 2meters 20 percent SF-96 on Chromosorb P). This material waschromatographed'on silica gel in benzene. The course of elution wasfollowed by gas chromatography. In this way 9.7 g. (27.2 percent yield)of pure compound was isolated; however, it was red-orange in color. Thecolor was easily removed by a flash distillation. An infrared spectrum(oil smear) of the pure compound showed strong absorption centered at1620 cm (C=O) and a broad region centered at 1200 cm *(C-F). The UVspectrum indicated A maximum n-hexane 292 mu (6 12,120) The NMR spectrum(ref, Si(CI-I )4) displayed a very sharp singlet of chemical shift 13.9ppm for the enolic hydrogen and a sharp singlet at 6.3 ppm for theolefinic hydrogen. A P NMR spectrum (ref., Freon 11) displayed a peak ofchemical shift 82.9 ppm for the methyl fluorines, a peak at 124.6 ppmfor the methylene fluorines, and peaks at 139.3 ppm, 148.0 ppm, and161.0 ppm for the ortho, para, and meta aromatic fluroines,respectively.

Anal. Calcd. for C H F O C, 37.10; H, 0.57; F, 53.35. Found: C, 37.28;H, 0.72; F, 53.40.

EXAMPLE Ill 4,4,5,5 ,6,6,6-Heptafluorol -pentafluorophenyl-1 ,3-hexanedione Dried sodium methoxide (0.1 mole) was suspended in anhydrousether (100 ml.) and ethyl perfluorobutyrate (24.2 g., 0.1 mole) inanhydrous ether (15 ml.) was added dropwise to the stirred suspension.The re-. action was exothermic and nearly all of the sodium methoxidereacted. The reaction mixture was cooled in an ice bath before theacetylperfluorobenzene (21.0 g., 0.1 mole) was added dropwise inanhydrous ether (100 ml.) over 1 hr After complete addition, thereaction mixture was allowed to warm to room temperature. There was notnoticeable evolution of heat, but the reaction mixture slowly turnedyellow as it warmed up. The reaction mixture was allowed to stand atroom temperature overnight under a nitrogen blanket. Workup was effectedby addition of concentrated sulfuric acid (3 ml.) in water (30ml.)followed' by extraction with ether and washing with water. The etherextract was dried over anhydrous sodium sulfate and evaporated in vacuo.The crude product was distilled through a column packed with glasshelices, 25.0 g., b.p. 888- 9/3.4 torr (62 percent yield). A gaschromatogram (150, 2 meter 20 percent SF-96 on Chromosorb P) of the pureliquid showed a retention time of 4.9 min. An infrared spectrum (oilsmear) of the compound showed strong absorption band at 1625 cm "(C=O)and a broad region centered at 1220 cm (C-F). The UV spectrum indicatedA maximum n-hexane' 292 mu (6 12,550). The NMR spectrum (ref., Si(CH=;)displayed a sharp peak of chemical shift at 13.9 ppm for the enolichydrogen and a sharp singlet at 6.2 ppm for the olefinic hydrogen. A FNMR spectrum (ref., Freon 11) displayed a peak of chemical shift at 80.7ppm for the methyl fluorines, peaks at 121.5

ppm and 126.7 ppm for themethylene fluorines, and peaks at 138.0 ppm,147.6 ppm, and 160.1 ppm for the ortho, para, and meta aromaticfluorines, respectively. g

Anal. Calcd. for C I-1 1 0 C, 35.49; H, 0.50; F, 56.14. Found: C, 35.36;H, 0.97; F, 56.09.

EXAMPLE 1V4,4,5,5,6,6,7,7,8,8,9,9,l0,10,10-Pentadecafluoro-lpentafluoro-phenyll,3- decanedione Sodium methoxide was prepared in situ by adding sodiummetal (2.4 g., 0.1 mole) to anhydrous methanol (50 ml.). After completereaction the excess methanol was distilled and the salt was thoroughlydried by a stream of nitrogen. The sodium methoxide was suspended inanhydrous ether ml.) and ethyl perfluorocaprylate (44.1 g., 0.1 mole) inanhydrous ether (25 ml.) was added dropwise to the stirred suspension.The reaction was exothermic and nearly all of the sodium methoxidereacted. The reaction mixture was cooled in an ice bath before theacetylperfluorobenzene (21.0 g., 0.1 mole) was added dropwise inanhydrous ether (100 ml.) over 1 hr. After complete addition thereaction mixture was allowed to warm to room temperature. Although therewas no noticeable evolution of heat, the reaction mixture slowly turnedyellow as it warmed up. After allowing the reaction mixture to stand atroom temperature overnight under a nitrogen blanket, a solution of 3 ml.of concentrated sulfuric acid in 30 ml. water was added. Followingextraction with ether, washing with water, and drying over anhydroussulfate, the ether extract was evaporated in vacuo. The crude productwas distilled through a column packed with glass helices, 22.2 g., b.p.107-1 l0/1.2 torr (37 percent yield). A gas chromato gram (200, 2 meter20 percent SF-96 on Chromosorb P) indicated one major peak with aretention time of 5.5 min. for the product, and one minor peak of higherboiling impurity. An NMR spectrum (ref, Si(CH showed a very sharp peakof chemical shift at 13.9 ppm for the enolic hydrogen and a peak at 6.2ppm for the olefinic hydrogen. The integrals of the two major peaks werein good agreement with theory (1:1). A F NMR spectrum (ref., Freon l 1displayed a peak of chemical shift at 80.7 ppm for the methyl fluorines,a region from 119.8 ppm to 125.4 ppm for the methylene fluorines, andpeaks at 137.1 ppm, 146.3 ppm, and 159.3,ppm for the ortho, para, andmeta aromatic fluorines, respectively. An infrared spectrum showedstrong absorption centered at 1620 cm (C=O) and a broad region centeredat 1220 cm *(C-F). The UV spectrum indicated A maximum n-hexane 293 mu(e 1 1,650).

Anal. Calcd. for tar- ,0,; C, 31.70; H, 0.33; F, 62.69. Found: C, 31,76;H, 0.59; F, 62.65.

The copper complex was prepared by shaking aqueous copper acetate withan ether solution of the B-diketone. The ether layer was washed withwater to remove excess copper acetate, dried over sodium sulfate andevaporated to dryness. The chelate could be destroyed in ether solutionby washing it several times with 15 percent sulfuric acid. The chelatewas found to be soluble in ether and chloroform, but only slightlysoluble in benzene, toluene, cyclohexane, dioxane and carbontetrachloride at room temperature. The chelate was recrystallized frombenzene to give m.p. 87-90. A second crystallization from benzene gavem.p. 8894; however, the sample had to be meticulously dried in vacuosince the solid was highly solvated. Further evidence of solvation wasseen'when a sample of the chelate was recrystallized from dioxane togive a product wherein Ar is a perfluoro aromatic radical which may ofmuch lighter green color and m.p. l34-l39. be substituted byperfluorinated lower alkyl groups A sample of the copper chelate twicerecrystallized and contains from six to 14 ring Carbon at m and frombenzene was submitted for analysis. n has a value of from to 15.

Anal. Calcd. for (Cwl-lF O )Cu: C, 30.17; H, 0.16; 2- A compound as setforth in claim 1 wherein Ar F, 59.66; Cu, 4.99. Found: C, 31.13; H,0.29; F, 59.88; contains six ring carbon atoms.

Cu, 4.85. 3. The compound set forth in claim 2 wherein n is What isclaimed is: zero.

A compound of the fol'mulal 4. The compound set forth in claim 2 whereinn is 1.

5. The compound set forth in claim 2 wherein n is 2.

II II 6. The compound set forth in claim 2 wherein n is 6. A -C CH2 2)n:i k

2. A compound as set forth in claim 1 wherein Ar contains six ringcarbon atoms.
 3. The compound set forth in claim 2 wherein n is zero. 4.The compound set forth in claim 2 wherein n is
 1. 5. The compound setforth in claim 2 wherein n is
 2. 6. The compound set forth in claim 2wherein n is 6.